Cementing back-pressure valve means



Feb. 17. 1925. 1,526,581

L. H. BACHE CEMENTiNG BACK PRESSURE VALVE MEANS Filed June 25'. 1925 Patented F eb. 17,, 1925.

LOUIS H BACHE, 0F TORRANCE, CALIFORNIA.

OEMENTIN G BACK-PRESSURE VALVE MEANS.

Applicationfiled .Tune 25, 1923.. Serial'No. 6 47570.

To all whom it may concern:

Be it'known that I, LOUIS H. BACI-IE, a citizen of the United States, residing at Torrance, in the county of Los Angeles and State of California, have invented a new'and useful 'Cement-ing Back-Pressure Valve Means, tion.

the type emplo ed to prevent cement from reentering a we 1 casing when such casing is lowered into position after the quantity of cement necessar to cement the well has been forced through the casing.

An object of the invention is to insure that the cement will be maintained on the outside of the casing until the cement has set.

Heretofore, in cementing a well, cement would ofttimes flow back into the casing due to the fact that the pressure, which the operator sought to maintain within the casing, lowered for some reason or other below that of the column of cement around the easing. In using this invention it is unnecessary to maintain pressure within the'casing after the cement has once been pumped into place.

The accompanying drawings illustrate one embodiment of the invention:

Figure 1 is a vertical mid section of cementing back pressure valve means constructed in accordance with the provisions of this inventi0n,'a fragment of easing being indicated in broken lines.

Fig. 2 is'a plan section on the line in: dicated by 2-2, Figure 1.

Fig. 3 is an inverted plan section-on the line indicated by 33, Fi 1.

In the drawings, a tubu ar member is indicated at 4 and may be, for example, the commonly employed casing shoe that is provided with internal screw threads 5 for screwing onto the lower end of the well casing, a fragment of which is indicated in broken lines a, Fig.1: Mounted within the memher 4 is a valve seat 6 which, in this instance,

is threaded at 7 into the lower end of the tubular member 4. It will be evident that any other satisfactory means may be employed for connecting the valve seat to the casing. The valve seat 6 may be secured against unscrewing by any suitable means and, in the instance shown, a hollow nut 8 is threaded into the lower end of the tubular member 4 approximately into contact with of which the following is an invenis a valve 10 having a stem 11 which slides Thls invention relates to valve means of the axis of the valve stem from the latch.

lishing a passage through the nut, valve seat and tubular member 4 for the passage of cement in the operation of cementing the well.

Adapted to close upon the valve seat 6 within a stem guide 12 that, in this instance, is formd integral with the valve seat 6. The valve stem 11 is provided near its upper end With a shoulder 13, and surrounding the valve stem between said shoulder'and the v stem guide 12 is a coil spring 14 tending to engagement with the which the valve is connected. In this 1nstance a suitable latch 15 is employed for releasably holding the valve 10 in open position. The latch is movably mounted in any suitable manner, being, in this instance, hinged or pivoted at 16 to the lower face of the valve seat at a sufficient distance from so that the latch, when retracted, will not interfere with the closing movement of the valve 10.

- When the latch 15 is aslant inwardly'and downwardly as in Figure 1. the lower end thereof engages in' an annular recess 17 in the valve 10 close to the periphery thereof, and further opening movement between the valve and valve seat will release the valve When the latch is disengaged from the valve, gravity may be relied upon to retract it, but preferably a coil s ring 18 is mounted on the pivot 16 with 1ts opposite ends engaging the latch valve. The pumping of the cement havingceased, .the back pressure 'will predominate thus causing the valve to close upon its seat and prevent the cement from running back into the casing which running, it it occurred, would lower the height of cement outside of the casing and permit such cement to set within the casing.

It will be clear from the foregoing that the valve is released from the holdingmeans or latch 15 by reason of there being greater fiuid pressure above the valve than vent back flow of the cement into the casing. In order to facilitate retracting of the valve 10, when it is desired to latch it in open position, the valve is provided on its lower face with an apertured lug 19. To retract the valve, a hook or other su'table device will be inserted tl'irough the opening 9 andengaged with the lug 19 and the hook will'be pulled to move the valve far enough from the seat 6 to permit the latch 15 to be swung into the position shown in Fig. 1.

I claim: t

1. Oementing back-pressure valve means, comprising a valve seat, a valve to close upon said seat, a spring tending to close the valve, and means to releasably hold the 'valve against closing, the valve being released from the holding means by pressure of the cement as it passes the valve.

2. cementing back-pressure valve means, comprising a valve seat, a valve to close upon said seat, a spring tending to close the valve, and means to releasably hold the valve in an open position, said valve being released from the holding means by fur ther opening movement between the valve and valve seat. v

3. Cementing back-pressure valve means, comprising a valve seat, a valve to close upon said seat, a spring tending to close the valve, and means to releasably h-old the valve in open position, said valve being released trom the holding-means by greater fluid pressure above the valve than the combined pressure exerted by the spring and the fluid beneath the valve.

4. The combination with a well casing, of

valve means at the lower end thereof to admit .of the passage of cement from the casing to the space therearonnd, said valve means being actuated by raising of the casing to prevent back flow of the cement into the caslngl Means ing a casing, and means associated with the casing and operating to admit of the passage of cement from the casing to the space thereartmnd, said means being actuated by pressure of the cement to prevent back flow of the cement in the casing. v

Signed at Torrance, Califi, this 14th day of June, 1923.

LOUIS H. BACHE.

for cementin a well com ris- 

